ABCD

Example

A
C
C
_
B
B
A
25
B
B
C
23
25
_
17
 
 
A
B
C
_
_
_

Solution

A
C
C
17
B
B
A
25
B
B
C
23
25
23
17
 
 
A
B
C
7
9
5
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ABCD
ABCD

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